X-ray apparatus.



No. 648,660. f Patented May I, I900.

B.. 'A. Fessmdnm. X-RAIY APPARATUS.

(Application flle'd Aug. 7, 1899'.

(No Model.)

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UNITED STATES PATENT Orrrcs.

X- RAY AP PAR ATU S.

SPECIFICATION forming part of Letters Patent hi o.,64=8,660, datedApplication filed August 7,1399. SerialNo.7-.6,398. Nomndel.)

To all 7071/0721. it 112107 concern/.-

Be it known that I, REGINALD A. FESSEN- DEN, a citizen of the UnitedStates, residing at Allegheny, in the county of Allegheny and State ofPennsylvania, have invented or discovered certain new and usefulImprovements in X-Ray Apparatus, of which improvements the following. isa specification.

The invention described herein relates to certain improvements inapparatus for the generation of Roentgen or X rays.

The invention has for its object a large increase in the quantity ofX-rays generated by a current of given potential and frequency,

as will be hereinafter more fully described and claimed.

In the accompanying drawing, forming a part of this specification, isshown a Crookes or focus tube having my improvements applied thereto.

As is well known to those skilled in the art,

the Roentgen or X' rays are generated by the impact ofelectrically-charged particles from the cathode-pole on a suitablesurfacesuch as glass, aluminium, platinum, &c. The cathode is usuallymade in the form, of a plate 1, suitably secured within the vacuum tubeor bulb 2, at or near one end thereof, and is connectedelectrically tothe negative pole of the electric generator. The X-ray generator ispreferably made in the form of a metal plate or disk 3,suitablysupportedin the bulb opposite the cathode 1, which preferably has theside toward the plate 3 made convex, so as to focus the cathode-currentson the plate 8. The generating or anticathodic plate is generallyarranged at an angle to the axis'of the cathode-plate, so that theX-rays will be directed through the side of the bulb, and the plate willoperate more efficiently in the production of X-rays if it isolectricallyconnected to the positive pole of the electric generator. Bythe impact of the electrically-charged par tieles from the cathode uponthe anticathodic surface the energy istransforined to X-rays or theX-rays are generated at points of impact'of the particles. 7

The anticathodic surface has heretofore been formed by a plate or'diskformed of or coated with platinum. I have found that a surface formed ofosmium is much more eflicient in the production of X-rays. In thepractice of-my invention the generating or transforming surface isformed of osmium, and by preference such surface is formed by the faceofa metal plate coated with and formed entirely of osmium. While it isconsidered to be the better practice to connect the anticathodic plateto the positive pole of the electric generator, I do not limit myself :3

to such an arrangement.

, I claim herein as my invention 1. As an'improvement in an apparatusfor the production of X-rays, an antieathodic plate having the surfaceexposed to the cathode-currents formed of osmium, substantially assetforth.

' 2. As an improvemcntin apparatus for the production of X-rays, ananticathodic plate formed of osmium, substantially as set forth.

As an improvement iii apparatus for the production of X-rays, ananticathodic plate connected to the positive pole of an electricgenerator and having the surface exposed to cathode-currents, form ed ofOlnllllhflilbStR-lltially as set forth. 1

In testimony whereof I have hereunto set my hand.

' v REGINALD. A. FESSENDEN. \Vitnesses:

DARWIN S.- WoLooT'r, F. EGAIT ER.

